Environmentally hazardous fluids such as acids, oils, and toxins, which can cause serious harm to the environment often need to be pumped throughout fluid flow systems from one location to another. Centrifugal pumps generally including a motor driven impeller affixed to a pump shaft are typically utilized in pumping such fluids. The pump shafts of such pumps are typically rotatably supported against radial movement and vibration by conventional pump shaft bearings (e.g. ball bearings). These bearings must be continually lubricated throughout the operation of the pump in order to reduce maintenance requirements and maintain a satisfactory operating life of the bearings and thus the pump.
Conventional lubricating fluid such as oil is typically used to lubricate such pump shaft bearings. The lubricating fluid is generally housed in a bearing lubrication chamber surrounding the pump shaft. When pumping such dangerous fluid materials, it is important that neither the lubricating fluid (e.g. oil) nor the fluid being pumped escape into the atmosphere or adjacent pump areas. Thus, seals must be provided adjacent the lubrication area(s).
Conventional pumps typically include ball bearings for supporting the pump shaft, the bearings being disposed within a misting or lubrication chamber. In the prior art, these shaft supporting ball bearings are typically lubricated by positioning the oil level within the lubrication chamber at a level or position about halfway up the bottom bearing ball. Maintaining the lubricating oil level at a position halfway up the bottom bearing ball necessarily means that when the shaft and supporting bearings are rotated, the balls must continuously plow through the lubricating oil in which they are partially submerged. This results in undesirable heat generation within the bearings and adjacent the pump shaft, this heat generation being caused by the friction created by the bearing balls continually passing through the lubricating oil. Such heat generation increases maintenance requirements and reduces the operating life of the bearings.
Furthermore, when the oil level within the pump lubrication chamber is disposed halfway up the bearing balls or higher as is conventional in the art, dirt or other contaminants present within the oil (or other lubricating fluid) are permitted to make their way into the annular bearing raceways in which the bearing balls are housed. The raceways are sandwiched between the inner and outer bearing frames. Because the bearing balls circumferentially rotate or roll around the pump shaft via these raceways, the presence of such contaminants therein causes increased wear of the bearings and thus additional maintenance.
Accordingly, it would satisfy a long-felt need in the art if a pump were to be developed so as to include an oil misting or lubrication chamber wherein the lubricating fluid (e.g. oil) level was continually disposed below the bearing balls so as to reduce heat generation within the bearings and the lubrication chamber and to limit the amount of dirt or other contaminants permitted to make their way into the bearing raceways.
Commonly owned U.S. Pat. No. 5,261,676, which is prior art to the instant invention due to an offer of sale more than one year before the instant filing date, discloses a centrifugal environmentally sealed pump including a bearing lubrication chamber. Disposed within the lubrication chamber is an oil dispenser affixed to the pump shaft for rotation therewith. The rotating dispenser of this patent has a plurality of rigid hoods which protrude therefrom, these hoods acting to pick up and disperse (i.e. splash and/or mist) the lubricating oil throughout the chamber so as to lubricate the pump shaft bearings therein. The hoods affixed to the rotating dispenser protrude so as to dip below the lubricating oil level within the chamber as the dispenser is rotated thereby scooping the oil from the reservoir area and dispersing it throughout the lubricating chamber and toward the adjacent bearings.
While the bearing lubrication system of U.S. Pat. No. 5,261,676 is excellent and provides good results, the hoods of the dispenser are required to plow through the lubricating oil within the lubrication chamber in order to properly disperse the oil throughout the chamber. Such plowing of the hoods generates undesirable heat within the lubrication chamber and requires the bearings to run at an increased temperature thereby resulting in increased maintenance requirements. Additionally, as a result of the hoods of the '676 dispenser picking up the lubricating oil and subsequently delivering it throughout the chamber, dirt and other contaminants such as rust, carbonized particles, etc. are sometimes directed toward the bearings along with the picked up lubricating oil, this also increasing maintenance requirements.
This application is related to commonly owned U.S. Ser. No. 08/246,150, filed on May 19, 1994 entitled "PUMP OIL MISTER", the disclosure of which is hereby incorporated herein by reference. While the oil misting assembly of Ser. No. 08/246,150 is excellent and provides superb lubrication of the adjacent pump bearings, the design of the rotating dispenser affixed to the pump shaft within the lubrication chamber causes a significant amount of windage adjacent the lubricating fluid surface or level when the pump shaft is rotated at extremely high speeds (e.g. greater than about 3,600 rpm). When such windage is present adjacent the oil level disposed in the reservoir portion of the lubrication chamber, a wake or the like is formed and the lubricating fluid level at the edges of the reservoir adjacent the pump shaft bearings is caused to rise. If the windage (or the operating speed of the pump) is severe enough (e.g. at extremely high speeds) adjacent the oil level, the wake is large enough so that the lubricating fluid level rises to a position adjacent the lower bearing ball(s) thus resulting in the bearing balls of at least one bearing plowing through the lubricating fluid or oil. As discussed above, it is undesirable for the bearing balls to be submerged within the lubricating fluid at the lower end of the lubrication chamber due to the resulting heat generation.
It is apparent from the above that there exists a need in the art for a pump including a bearing lubrication system wherein: 1) the lubricating fluid level is maintained at a level below the bearing balls disposed in the chamber so as to reduce heat generation caused by the bearing balls plowing through and being submerged within the lubricating fluid; 2) the rotating dispenser or disc affixed to the pump shaft within the lubrication chamber produces minimal or reduced windage adjacent the lubricating fluid when operated at high speeds (high rpms) thus allowing the fluid level to be maintained at a substantially constant level throughout the chamber; and 3) clean, cool, and effective lubricating fluid is maintained along the exterior or outer sides of the bearing assemblies between the bearing frame seals and adjacent bearing balls so as to extend the life of the bearings.
It is the purpose of this invention to fulfill the above-described needs in the art, as well as other needs apparent to the skilled artisan from the following detailed description of this invention.